This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. PET and MRI have been used to monitor functional activity of the human brain in subjects awake, but at rest. These studies have demonstrated that certain cortical regions known to be activated when subjects engage in social cognition tasks and introspection. We monitored resting cognitive brain activity in chimpanzees using FDG-PET. FDG was administered orally while the animal is resting in its home enclosure;after an appropriate uptake period, the animals were anesthetized and given a PET scan. During the reporting period, our results indicated that chimpanzees and humans activate many of the same cortical areas at rest, specifically, the medial frontal and medial parietal/posterior cingulate areas involved in social judgement and recollection of personal memories. Only humans, however, show left-lateralized activity in frontal and temporoparietal regions associated with language.